In an example of a conventional headlamp of a vehicle, as shown in FIGS. 9 and 10, a bulb 2 and a reflector 3 are disposed in the interior of a lamp housing 1 made of a resin, and a lamp lens 5 is assembled over an opening 4 formed in the lamp housing 1 on a side thereof which faces the front of the vehicle. A packing 8 is interposed between an end edge 6 of the lamp housing 1 by which the opening 4 is defined and an end edge 7 of the lamp lens 5, and the lamp housing 1 and the lamp lens 5 are locked together by clips 9 which are each formed of a steel spring plate and which are disposed along an outer circumferential direction of the housing and lens at appropriate intervals.
In order to ensure the locking by the clips 9, the followings are needed.
Firstly, a projection 10 which projects towards the rear in a longitudinal direction of the vehicle is formed on the end edge 6 of the lamp housing 1, and a projection 11 which projects towards the front in the longitudinal direction of the vehicle is formed on the end edge 7 of the lamp lens 5. A clip 9 is then brought into engagement with these projections 10, 11. In this way, the locking by the clip 9 can be ensured.
Incidentally, when molding the lamp housing 1, in order to form a recessed portion in which the packing 8 is disposed in the end edge 6 on a side thereof which faces the front of the vehicle, a mold 12 indicated by a two-dot chain line needs to be drawn towards the front side of the vehicle (leftwards in FIG. 10) as indicated by an arrow A. On the other hand, in order to form the projection 10 on the end edge 6 on a side thereof which faces the rear of the vehicle, a mold 13 indicated by the two-dot chain line needs to be drawn towards the rear side of the vehicle (rightwards in FIG. 10) as indicated by an arrow B.
There may be a case in which a mounting seat surface of the lamp housing 1 or a reinforcement rib 14 (hereinafter, simply referred to as a rib 14) is provided on an outer circumferential wall surface of the lamp housing 1 in the vicinity of an end of the projection 10 on the end edge 6 which faces the rear of the vehicle. As this occurs, while the projection 10 and the rib 14 are desired to be molded at the same time, since the rib 14 is situated on the drawing path of the mold 13 (in the direction indicated by the arrow B), the mold 13 cannot be drawn as desired, and therefore, it is extremely difficult in reality to form the projection 10 and the rib 14 at the same time. Thus, the degree of freedom in designing the lamp housing 1 is largely limited. Also, the number of molds is increased due to the provision of the rib 14, this leading to a problem that the production costs are increased.
An object of the invention is to provide a method for easily molding a projection on an end edge defining an opening in a housing, which projects towards an opposite side of the end edge to the opening, and to provide a housing structure related to the method.